Photography was announced in 1839, and in 1840, Henry Talbot, who had been struggling to improve his original process, came up with this understanding that actually you could chemically develop photographs into existence, rather than use the agency of light. And in 1841 he went public with it and in those days he called it the calotype.

Talbot's process gave you the negative and positive structure for photography, which was then adopted for the next 150 years. So it's the foundation on which all our subsequent photography rested.

Initially, Talbot was very, kind of, guarded with his photography. Because you've got to remember, this was a new way of seeing the world. It was not the way that you look with your eyes. This was monocular vision, a camera vision. So he began experimenting. And he began making photographs, first of all, of very static objects, because exposures still were twenty, thirty minutes long. And he would photograph trees in the winter, with the branches outlined against the sky, Gothic ruins, buildings, and photograph articles of china, haystacks, all of that kind of stuff—which were around him at his country home at Lacock Abbey. And it was only later that he began to experiment more widely and travel abroad.

Talbot was a very interesting character in the sense that he was a polymath, came from the English landed gentry. He was in the fortunate position of having sufficient income to be able to, kind of, be of independent means. We later called them the "gentlemen amateurs." But he was highly educated, fluent in Greek and Latin, he was interested in the sciences, in botany. He'd done research into light, he subsequently did research into Assyriology, as well as invent photography.

First of all, he patented it—or "patented" it, as you would say in America—that then led to a limited number of people taking up licenses to use it. But people who were within his family circle and his social circle, he encouraged to use freely. They could use his process, and it was largely limited to people of his own class and his own equals.

Interestingly, in England, the patent laws there didn't apply to Scotland. So Scotland—it was without a patent. And there was a whole flourishing of this early photography up in Scotland, independent of what was happening in England. And so, we have major photographers—some of whom are in the show, like Hill and Adamson. And they flourished and were—now widely acknowledged as the, kind of, first masters of photography.

And after 1850 we have it being used all throughout Britain in photographic societies and by people who would take—with amateur photography—by people who were traveling in Italy and Spain and France, people who were traveling and working in India. So the use of paper negative photography became very widespread after 1851, which is a complete overturn from the general accepted history.

The calotype itself is a paper negative. And that paper negative, because it's made of paper, as you print it, the fibers of the paper itself soften the detail of the image. It's not like transparent film. It's not like glass, on which many of the photographs were made in the nineteenth century. This paper introduced a fibrous texture and gave a softness, which was—actually they found very appealing. Part of the reason that the calotype was taken up by people was, purely and simply, because it had an artistic expression. It was felt to be close to the works of Rembrandt. The idea that this could be an artistic means of expression was very important.

The calotype never really entered into the trade, despite Talbot's best efforts. He tried to commercialize it. He was trying to market it. He did, in every way possible, try to market his process. But he was eclipsed by the daguerreotype.

In Britain, during the eighteenth century, many of the, kind of, landed aristocracy went and finished their education on what was called the Grand Tour. And by the time we get to the mid-nineteenth century, we have their kind of successors coming along and thinking, "Well, I'm going to go on the Grand Tour, but instead of taking a sketchpad and a watercolor box and a notepad, what I'm going to do is take my camera." And so these people went out and explored the face of Europe with their cameras. And they brought back extraordinarily complex images, which were fundamentally, radically different to the way in which we normally expect to see drawings of landscape, classical landscapes in classical size. In India, where the climate was so difficult to deal with, paper negative photography and the calotype were absolutely ideally suited because it was a very tolerant process under extremes of heat. And so, we have a new breed of photographers working in India. And these photographers were, in fact, people who were employed by the East India Company. They were people who were in the military. They were part of the British administration of India. And they are very muscular photographs, they're large-format, they photographed the temples and the shrines and the landscapes, and after 1857, after the Indian uprising in '57, they go around and photograph all the sites of that conflict. And there's a rich body of work. And this show, if nothing else, shows that photography was an entirely personal and human activity.

Finding these calotypes was a great difficulty. And in order to do that, I had to identify who the calotypists were. I created a long list of something like two hundred names, and armed with that I then went in search of all the, kind of, major archives. I did the initial legwork and identified these, and then my co-curators came with me and we worked together and selected the work. But it took many years to actually find all this work and pull it together. And as a result, we have many new names that are not in the registered canon of photography. And that's what's exciting.

I think if, when we look at the show, one of the things that you have to realize is the endeavor that kind of went into making these photographs. They're not made by digital cameras. They are made as a result of extreme concentration and an appreciation of light. What we do today, we make a photograph and it just goes click and we take it and it's done. And we allow the camera to do all the work. These guys had to think about where to position the camera, they were thinking about their response to light, the way it described a building or a tree or a landscape. And they are very carefully composed and structured studies. And we can take from that. I think we've become too prolific. We make little snapshots. We make them so that they go click, click, click, and we put them in the album. We never look at them again really. These are studies for contemplation. These are photographs that we need to dwell on and linger over and enjoy and savor.

Impressed by Light is on view at The Metropolitan Museum of Art through the 31st of December, 2007.

The exhibition is made possible by the Hite Foundation.

It was organized by The Metropolitan Museum of Art, New York, and the National Gallery of Art, Washington, D.C.